This section provides background information related to the present disclosure which is not necessarily prior art.
With the fast development of display technology, the technology of a semiconductor element as the key of a display device has also been developed fast. For a conventional display device, an Organic Light Emitting Diode (OLED) as a current-type light emitting component, because of its self-emission, fast response, wide viewing angle, and being manufacturable on a flexible substrate and the like, is increasingly being used in the high performance display.
OLED can be divided into Passive Matrix Driving OLED (PMOLED) and Active Matrix Driving OLED (AMOLED) by the driving manner. Since an AMOLED display has advantages such as low manufacturing costs, high response speed, power saving, direct current drive adapted for portable devices, large operating temperature range, etc., it is expected to be a next generation new flat panel display replacing the liquid crystal display (LCD).
In a conventional AMOLED display panel, each OLED includes a plurality of Thin Film Transistor (TFT) switch circuits. However, characteristics of production process and polysilicon cause electrical parameters such as threshold voltage Vth, mobility, etc. to usually fluctuate in the production of the TFT switch circuits on a large-area glass substrate, so that current flowing through the OLED component in the AMOLED display panel not only changes with a ON-voltage stress generated when the TFTs have been turned on for a long time, but also vary with the drift of the threshold voltage Vth of the TFTs. This will affect luminance uniformity and luminance constancy of the display, thereby reducing picture performance and quality of the display.